A conveying robot places a substrate when the substrate is placed on a stage of a charged particle beam photolithography apparatus. When the substrate is deviated from a normal placement position on the stage, there is generated a problem in that a lithography pattern is misaligned on the substrate.
Therefore, there has been developed a method in which a reference block is provided on a stage and the substrate is aligned on the stage using the reference block. However, in the method, unfortunately particles are generated by contact of the substrate with the reference block.
JP-A 2008-177256 discloses a charged particle beam photolithography apparatus including a projection unit that obliquely illuminates an upper surface of the substrate with a laser beam, a light receiving unit that receives light reflected from the substrate, and a unit that computes a height of the substrate.